"Sorry Dave, that sounds like psychomystical claptrap to me. The fact is that 
using mathematics, and our knowledge of the physical laws, we already have a 
Rosetta Stone to relate with any technological society of aliens. If they were 
non technological, I'm not sure it would be so easy. The fact that we would be 
two intelligent races with scientists
makes for a huge overlap of common ground from which to build greater 
communication."
First of all, what aspects of my post make it sound like "psychomystical 
claptrap"?  I think the concept of resonance between systems (broadly meaning 
that they cause each other to behave similarly) is a farily scientific concept 
(tuning forks are the classic example).  The idea the humans mimic each other 
is a matter of observable fact.  I don't see anything in my post that I would 
imagine someone could see as "psychomystical claptrap".  
I understand what you're saying about the Rosetta Stone and using our common 
base of scientific knowledge to develop forms of communication with aliens.  
However, I can conceive of possible alien beings who are technologically 
advanced and who have a very good understanding of the regularities of the 
universe (the knowledge that we discover through science), but whose concepts 
and ways of thinking are still profoundly different than ours.  I am thinking 
that our way of doing science and finding out how the universe works is only 
one of many ways to approach understanding the universe.  It may be that our 
science is simply a way that is especially well suited to the human brain.  
I imagine that alien beings would have developed their own, unique ways of 
developing accurate knowledge, which would likely be profoundly different from 
our own.  They may come to understand the various properties of the different 
elements and learn how to take advantage of those properties, but the way they 
organize their knowledge and represent it to each other may be quite 
profoundly different from our Periodic Table of the Elements.  It makes sense 
to us to arrange all the elements on a chart, grouped according to similar 
properties and in order of atomic weight, but it only makes sense because of 
the particular ways that we have developed to think about things.  Evolution 
on a different planet would likely yield intelligent beings with very 
different ways of thinking about things and approaching things.
Humans seem to have a hard time imagining that intelligent beings might think 
in ways profoundly different than we do.  We tend to think that our way of 
intelligence is the only way.  It's difficult to imagine other ways of 
thinking; they are too alien to our minds.  Humans also tend to  imagine that 
intelligent aliens will be humanoid in shape, or something reasonably similar. 
 We have a hard time imagining intelligent beings in shapes *very* different 
than our own.
Then there's the question of how the aliens would likely communicate with each 
other.  Would they vibrate the air, like we do?  Perhaps they would make 
intricate bodily movements and use some kind of sonar to observe each other 
move.  Perhaps they will have ways of communicating massive amounts of 
information in parallel, rather than in a stream, like we do.  Maybe they will 
have developed some sort of technology so that they stimulate each other's 
minds more directly, and their communications would be so subtle that we would 
consider it telepathy.  Their forms of communication may be so profoundly 
different than ours, and their ways of representing knowledge in their minds 
may be so profoundly different, that even if they understand the basic 
properties of the universe to the degree we do and have the same basic 
knowledge, we wouldn't be able to recognize how they've encoded that knowledge 
because we wouldn't understand how they even communicate knowledge to each 
other.  If their knowledge is being communicated between each of the aliens by 
subtle technological links between their minds, then it would be very 
difficult to understand the workings of their communication devices, which 
would most likely be almost seamlessly integrated with their cognitive organs.
Yeah, if they had a periodic chart written down somewhere, then we could 
compare it with ours and understand a little of their language, but what if 
they don't write anything down?  What if all their communication is 
"telepathic"?  How do we crack into their communication systems to even have a 
start at understanding the information that they are passing back and forth?  
And then how do we understand what they're "talking" about?  Maybe each of 
them has all the properties of physical matter memorized, so they no longer 
talk about it; they just refer to that set of knowledge with arbitrary 
symbols.  Then we would never see their scientific knowledge being 
communicated between them, only arbitrary symbols that are meaningful only to 
the aliens themselves.  
To communicate with them, we have to understand the ways they link concepts 
together and what symbols they use to represent which concepts. This is likely 
to be as much of an evolved and tangled mess as human thinking and human 
language.  I don't think we would have much hope of untangling their mess of 
concepts and symbols if we ever met an alien species.
Language is an evolved technological device, with symbols pointing to various 
concepts, which are linked to other concepts with varying degrees of fuzziness 
inside each individual's mind.  Language grows as we invent new symbols to 
point to our shared concepts and develop new fuzzy links between concepts.  
Language grows and evolves very much like an organism.  Minor mutations are 
constantly being made to the symbolic structure.  It's also very much like a 
computer program that keeps getting added to and changed here and there until 
it is almost unrecognizable compared to what it was and is very complex and 
messy.
Michael asks, "Who ever said that humans have a  "low" level of 
communication?"
I did.  It was right in my post.  Did you not see it? :-)
Humans DO have a low level of communication.  Most of the activities and 
thoughts occurring in our brains have no representation in our languages.  We 
can look at the sky, but can we communicate the color blue?  No; we can only 
refer the person we are talking to, to their experience of the color blue.  
When we're communicating with each other, we're basically referring each other 
to common, similar memories and experiences.  We can only really communicate 
about common experiences and concepts.  
Also, it is extremely difficult for us to communicate with each other about 
experiences we have in common but which haven't been talked about before, so 
no symbols have been developed yet to represent that common experience.  
Various bodily sensations and nuances of emotion are common, mutual 
experiences for which we haven't yet developed symbols, and so we cannot 
really communicate with each other about these experiences, because we don't 
know what sounds or images to make to get the other person to remember the 
experience we are wanting to refer them to.
Most of our thoughts have to do mainly with our own specific, individual 
memories and experiencs, and these thoughts cannot be shared through language 
because only the individual thinking them has the proper background (memories) 
to understand those thoughts. 
Do you understand what I am saying?  It's very difficult to communicate these 
ideas well.  Especially since I don't know how much background you have in 
these areas, and I don't know how much to explain and how much to assume you 
already know.  I also don't know how you think about things and link up 
concepts, so I don't know if I'm triggering off your concepts in the proper 
order so that you form the links that I am trying to get you to form with this 
communication.
Effective communication is very difficult to achieve between humans.  It is an 
art that requires much training and practice.  
- David Musick
  - question tradition -
P.S.  E. Shaun Russell, you wanted to start a thread on semantics.  This is it 
(in case you didn't notice).